Solution for C# occurence but not using LINQ

Question

For a given string in C# count the number of occurrences of each >character that repeats itself (occurs more than once).

Example:

string str = "abcdzefazz"; 

Expected output:

Character a has 2 occurrences. 
Character z has 3 occurrences.

Answer 1

Well, for No Linq solution you can use good old foreach loop with a help of dictionary Dictionary<char, int>. Here Key is character itself and Value is occurence:

  string str = "abcdzefazz";

  ...

  Dictionary<char, int> occurence = new Dictionary<char, int>();

  foreach (char c in str)
    if (occurence.TryGetValue(c, out value))
      occurence[c] = value + 1;
    else
      occurence.Add(c, 1);

When you want to know occurence (number) of ch character:

  char ch = 'z';

  ...

  int number = occurence.TryGetValue(ch, out value) ? value : 0;   

To print all occurence, just loop over the dictionary:

  foreach (var pair in occurence)
    Console.WriteLine($"Character {pair.Key} has {pair.Value} occurrences");

To obtain all characters with more then 1 ocurrence, just add condition:

  foreach (var pair in occurence)
    if (pair.Value > 1)
      Console.WriteLine($"Character {pair.Key} has {pair.Value} occurrences");